Any cool moist place will attract termites especially if you got wood on the menu. LOL. I have found termites in my mulch on a couple of occasions but I ran and got the bug spray and sprayed the whole area then waited for it to dry before I put the mulch back.
I read that you should keep mulch six inches away from your foundation because they will tunnel under the mulch.
Also you can sprinkle borax on your piles to keep them from getting in to the mulch, they say the borax removes the waxy coating on the termites body. However I have insecticidal soap for that and also ammonia works. That would explain why I do not see them that often. Ammonia also kills slugs so I am always spraying it around hostas and other plants that are on the menu. You might want to get a jug yourself.